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Cho JY, Rumschlag JA, Tsvetkov E, Proper DS, Lang H, Berto S, Assali A, Cowan CW. MEF2C Hypofunction in GABAergic Cells Alters Sociability and Prefrontal Cortex Inhibitory Synaptic Transmission in a Sex-Dependent Manner. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100289. [PMID: 38390348 PMCID: PMC10881314 DOI: 10.1016/j.bpsgos.2024.100289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 02/24/2024] Open
Abstract
Background Heterozygous mutations or deletions of MEF2C cause a neurodevelopmental disorder termed MEF2C haploinsufficiency syndrome (MCHS), characterized by autism spectrum disorder and neurological symptoms. In mice, global Mef2c heterozygosity has produced multiple MCHS-like phenotypes. MEF2C is highly expressed in multiple cell types of the developing brain, including GABAergic (gamma-aminobutyric acidergic) inhibitory neurons, but the influence of MEF2C hypofunction in GABAergic neurons on MCHS-like phenotypes remains unclear. Methods We employed GABAergic cell type-specific manipulations to study mouse Mef2c heterozygosity in a battery of MCHS-like behaviors. We also performed electroencephalography, single-cell transcriptomics, and patch-clamp electrophysiology and optogenetics to assess the impact of Mef2c haploinsufficiency on gene expression and prefrontal cortex microcircuits. Results Mef2c heterozygosity in developing GABAergic cells produced female-specific deficits in social preference and altered approach-avoidance behavior. In female, but not male, mice, we observed that Mef2c heterozygosity in developing GABAergic cells produced 1) differentially expressed genes in multiple cell types, including parvalbumin-expressing GABAergic neurons, 2) baseline and social-related frontocortical network activity alterations, and 3) reductions in parvalbumin cell intrinsic excitability and inhibitory synaptic transmission onto deep-layer pyramidal neurons. Conclusions MEF2C hypofunction in female, but not male, developing GABAergic cells is important for typical sociability and approach-avoidance behaviors and normal parvalbumin inhibitory neuron function in the prefrontal cortex of mice. While there is no apparent sex bias in autism spectrum disorder symptoms of MCHS, our findings suggest that GABAergic cell-specific dysfunction in females with MCHS may contribute disproportionately to sociability symptoms.
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Affiliation(s)
- Jennifer Y. Cho
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
- Medical Scientist Training Program, Medical University of South Carolina, Charleston, South Carolina
| | - Jeffrey A. Rumschlag
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Evgeny Tsvetkov
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
| | - Divya S. Proper
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Stefano Berto
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
| | - Ahlem Assali
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
| | - Christopher W. Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
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Privitera F, Piccini F, Recalcati MP, Presi S, Mazzola S, Carrera P. APC-Related Phenotypes and Intellectual Disability in 5q Interstitial Deletions: A New Case and Review of the Literature. Genes (Basel) 2023; 14:1505. [PMID: 37510409 PMCID: PMC10379344 DOI: 10.3390/genes14071505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
The 5q deletion syndrome is a relatively rare condition caused by the monoallelic interstitial deletion of the long arm of chromosome 5. Patients described in literature usually present variable dysmorphic features, behavioral disturbance, and intellectual disability (ID); moreover, the involvement of the APC gene (5q22.2) in the deletion predisposes them to tumoral syndromes (Familial Adenomatous Polyposis and Gardner syndrome). Although the development of gastrointestinal tract malignancies has been extensively described, the genetic causes underlying neurologic manifestations have never been investigated. In this study, we described a new patient with a 19.85 Mb interstitial deletion identified by array-CGH and compared the deletions and the phenotypes reported in other patients already described in the literature and the Decipher database. Overlapping deletions allowed us to highlight a common region in 5q22.1q23.1, identifying KCNN2 (5q22.3) as the most likely candidate gene contributing to the neurologic phenotype.
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Affiliation(s)
- Flavia Privitera
- Laboratory of Clinical Molecular Genetics and Cytogenetics, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Flavia Piccini
- Laboratory of Clinical Molecular Genetics and Cytogenetics, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Maria Paola Recalcati
- Laboratory of Clinical Molecular Genetics and Cytogenetics, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Silvia Presi
- Laboratory of Clinical Molecular Genetics and Cytogenetics, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Silvia Mazzola
- Medical Genetics, ASST del Garda, Desenzano, 25015 Brescia, Italy
| | - Paola Carrera
- Laboratory of Clinical Molecular Genetics and Cytogenetics, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
- Unit of Genomics for Diagnosis of Human Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
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3
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Mohajeri K, Yadav R, D'haene E, Boone PM, Erdin S, Gao D, Moyses-Oliveira M, Bhavsar R, Currall BB, O'Keefe K, Burt ND, Lowther C, Lucente D, Salani M, Larson M, Redin C, Dudchenko O, Aiden EL, Menten B, Tai DJC, Gusella JF, Vergult S, Talkowski ME. Transcriptional and functional consequences of alterations to MEF2C and its topological organization in neuronal models. Am J Hum Genet 2022; 109:2049-2067. [PMID: 36283406 PMCID: PMC9674968 DOI: 10.1016/j.ajhg.2022.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 09/29/2022] [Indexed: 01/26/2023] Open
Abstract
Point mutations and structural variants that directly disrupt the coding sequence of MEF2C have been associated with a spectrum of neurodevelopmental disorders (NDDs). However, the impact of MEF2C haploinsufficiency on neurodevelopmental pathways and synaptic processes is not well understood, nor are the complex mechanisms that govern its regulation. To explore the functional changes associated with structural variants that alter MEF2C expression and/or regulation, we generated an allelic series of 204 isogenic human induced pluripotent stem cell (hiPSC)-derived neural stem cells and glutamatergic induced neurons. These neuronal models harbored CRISPR-engineered mutations that involved direct deletion of MEF2C or deletion of the boundary points for topologically associating domains (TADs) and chromatin loops encompassing MEF2C. Systematic profiling of mutation-specific alterations, contrasted to unedited controls that were exposed to the same guide RNAs for each edit, revealed that deletion of MEF2C caused differential expression of genes associated with neurodevelopmental pathways and synaptic function. We also discovered significant reduction in synaptic activity measured by multielectrode arrays (MEAs) in neuronal cells. By contrast, we observed robust buffering against MEF2C regulatory disruption following deletion of a distal 5q14.3 TAD and loop boundary, whereas homozygous loss of a proximal loop boundary resulted in down-regulation of MEF2C expression and reduced electrophysiological activity on MEA that was comparable to direct gene disruption. Collectively, these studies highlight the considerable functional impact of MEF2C deletion in neuronal cells and systematically characterize the complex interactions that challenge a priori predictions of regulatory consequences from structural variants that disrupt three-dimensional genome organization.
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Affiliation(s)
- Kiana Mohajeri
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, USA
| | - Rachita Yadav
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Eva D'haene
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Philip M Boone
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Serkan Erdin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Dadi Gao
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mariana Moyses-Oliveira
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Riya Bhavsar
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Benjamin B Currall
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Kathryn O'Keefe
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Nicholas D Burt
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Chelsea Lowther
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Diane Lucente
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Mathew Larson
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Claire Redin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Olga Dudchenko
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Center for Theoretical Biological Physics and Department of Computer Science, Rice University, Houston, TX, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Center for Theoretical Biological Physics and Department of Computer Science, Rice University, Houston, TX, USA; UWA School of Agriculture and Environment, The University of Western Australia, Crawley, WA 6009, Australia; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech, Pudong, China
| | - Björn Menten
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Derek J C Tai
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - James F Gusella
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, USA; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Sarah Vergult
- Center for Medical Genetics, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, USA.
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4
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McChesney N, Barth JL, Rumschlag JA, Tan J, Harrington AJ, Noble KV, McClaskey CM, Elvis P, Vaena SG, Romeo MJ, Harris KC, Cowan CW, Lang H. Peripheral Auditory Nerve Impairment in a Mouse Model of Syndromic Autism. J Neurosci 2022; 42:8002-8018. [PMID: 36180228 PMCID: PMC9617620 DOI: 10.1523/jneurosci.0253-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/27/2022] [Accepted: 08/13/2022] [Indexed: 11/21/2022] Open
Abstract
Dysfunction of the peripheral auditory nerve (AN) contributes to dynamic changes throughout the central auditory system, resulting in abnormal auditory processing, including hypersensitivity. Altered sound sensitivity is frequently observed in autism spectrum disorder (ASD), suggesting that AN deficits and changes in auditory information processing may contribute to ASD-associated symptoms, including social communication deficits and hyperacusis. The MEF2C transcription factor is associated with risk for several neurodevelopmental disorders, and mutations or deletions of MEF2C produce a haploinsufficiency syndrome characterized by ASD, language, and cognitive deficits. A mouse model of this syndromic ASD (Mef2c-Het) recapitulates many of the MEF2C haploinsufficiency syndrome-linked behaviors, including communication deficits. We show here that Mef2c-Het mice of both sexes exhibit functional impairment of the peripheral AN and a modest reduction in hearing sensitivity. We find that MEF2C is expressed during development in multiple AN and cochlear cell types; and in Mef2c-Het mice, we observe multiple cellular and molecular alterations associated with the AN, including abnormal myelination, neuronal degeneration, neuronal mitochondria dysfunction, and increased macrophage activation and cochlear inflammation. These results reveal the importance of MEF2C function in inner ear development and function and the engagement of immune cells and other non-neuronal cells, which suggests that microglia/macrophages and other non-neuronal cells might contribute, directly or indirectly, to AN dysfunction and ASD-related phenotypes. Finally, our study establishes a comprehensive approach for characterizing AN function at the physiological, cellular, and molecular levels in mice, which can be applied to animal models with a wide range of human auditory processing impairments.SIGNIFICANCE STATEMENT This is the first report of peripheral auditory nerve (AN) impairment in a mouse model of human MEF2C haploinsufficiency syndrome that has well-characterized ASD-related behaviors, including communication deficits, hyperactivity, repetitive behavior, and social deficits. We identify multiple underlying cellular, subcellular, and molecular abnormalities that may contribute to peripheral AN impairment. Our findings also highlight the important roles of immune cells (e.g., cochlear macrophages) and other non-neuronal elements (e.g., glial cells and cells in the stria vascularis) in auditory impairment in ASD. The methodological significance of the study is the establishment of a comprehensive approach for evaluating peripheral AN function and impact of peripheral AN deficits with minimal hearing loss.
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Affiliation(s)
- Nathan McChesney
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeremy L Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeffrey A Rumschlag
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Junying Tan
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Adam J Harrington
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Carolyn M McClaskey
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Phillip Elvis
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Silvia G Vaena
- Hollings Cancer Institute, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Martin J Romeo
- Hollings Cancer Institute, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kelly C Harris
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Christopher W Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
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5
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Bailon-Zambrano R, Sucharov J, Mumme-Monheit A, Murry M, Stenzel A, Pulvino AT, Mitchell JM, Colborn KL, Nichols JT. Variable paralog expression underlies phenotype variation. eLife 2022; 11:e79247. [PMID: 36134886 PMCID: PMC9555865 DOI: 10.7554/elife.79247] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
Human faces are variable; we look different from one another. Craniofacial disorders further increase facial variation. To understand craniofacial variation and how it can be buffered, we analyzed the zebrafish mef2ca mutant. When this transcription factor encoding gene is mutated, zebrafish develop dramatically variable craniofacial phenotypes. Years of selective breeding for low and high penetrance of mutant phenotypes produced strains that are either resilient or sensitive to the mef2ca mutation. Here, we compared gene expression between these strains, which revealed that selective breeding enriched for high and low mef2ca paralog expression in the low- and high-penetrance strains, respectively. We found that mef2ca paralog expression is variable in unselected wild-type zebrafish, motivating the hypothesis that heritable variation in paralog expression underlies mutant phenotype severity and variation. In support, mutagenizing the mef2ca paralogs, mef2aa, mef2b, mef2cb, and mef2d demonstrated modular buffering by paralogs. Specifically, some paralogs buffer severity while others buffer variability. We present a novel, mechanistic model for phenotypic variation where variable, vestigial paralog expression buffers development. These studies are a major step forward in understanding the mechanisms of facial variation, including how some genetically resilient individuals can overcome a deleterious mutation.
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Affiliation(s)
- Raisa Bailon-Zambrano
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Juliana Sucharov
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Abigail Mumme-Monheit
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Matthew Murry
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Amanda Stenzel
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Anthony T Pulvino
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Jennyfer M Mitchell
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Kathryn L Colborn
- Department of Surgery, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - James T Nichols
- Department of Craniofacial Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
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Fernández Hernández L, Alcántara Ortigoza MA, Ramos Angeles SE, González-Del Angel A. Cleft Lip Palate in a Patient with 5q14.3 Deletion Syndrome: A Possible Unreported Feature? Cytogenet Genome Res 2022; 161:556-563. [PMID: 35021179 DOI: 10.1159/000521225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/29/2021] [Indexed: 11/19/2022] Open
Abstract
5q14.3 deletion syndrome (MIM#613443) is an uncommon but well-known syndrome characterized by intellectual disability, epilepsy, hypotonia, brain malformations, and facial dysmorphism. Most patients with this syndrome have lost one copy of the MEF2C gene (MIM*600662), whose haploinsufficiency is considered to be responsible for the distinctive phenotype. To date, nearly 40 cases have been reported; the deletion size and clinical spectrum are variable, and at least 6 cases without MEF2C involvement have been documented. We herein report the clinical and cytogenomic findings of an 11-year-old girl who has a 5q14.3q21.1 de novo deletion that does not involve MEF2C but shares the clinical features described in other reported patients. Moreover, she additionally presents with bilateral cleft-lip palate (CLP), which has not been previously reported as a feature of the syndrome. The most frequent syndromic forms of CLP were ruled out in our patient mainly by clinical examination, and Sanger sequencing was performed to discard the presence of a TBX22 gene (MIM*300307) defect. Our report suggests CLP as a possible unreported feature and redefines the critical phenotypic regions of 5q14.3 deletion syndrome.
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7
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Harrington AJ, Bridges CM, Berto S, Blankenship K, Cho JY, Assali A, Siemsen BM, Moore HW, Tsvetkov E, Thielking A, Konopka G, Everman DB, Scofield MD, Skinner SA, Cowan CW. MEF2C Hypofunction in Neuronal and Neuroimmune Populations Produces MEF2C Haploinsufficiency Syndrome-like Behaviors in Mice. Biol Psychiatry 2020; 88:488-499. [PMID: 32418612 PMCID: PMC7483399 DOI: 10.1016/j.biopsych.2020.03.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 03/02/2020] [Accepted: 03/20/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND Microdeletions of the MEF2C gene are linked to a syndromic form of autism termed MEF2C haploinsufficiency syndrome (MCHS). MEF2C hypofunction in neurons is presumed to underlie most of the symptoms of MCHS. However, it is unclear in which cell populations MEF2C functions to regulate neurotypical development. METHODS Multiple biochemical, molecular, electrophysiological, behavioral, and transgenic mouse approaches were used to characterize MCHS-relevant synaptic, behavioral, and gene expression changes in mouse models of MCHS. RESULTS We showed that MCHS-associated missense mutations cluster in the conserved DNA binding domain and disrupt MEF2C DNA binding. DNA binding-deficient global Mef2c heterozygous mice (Mef2c-Het) displayed numerous MCHS-related behaviors, including autism-related behaviors, changes in cortical gene expression, and deficits in cortical excitatory synaptic transmission. We detected hundreds of dysregulated genes in Mef2c-Het cortex, including significant enrichments of autism risk and excitatory neuron genes. In addition, we observed an enrichment of upregulated microglial genes, but this was not due to neuroinflammation in the Mef2c-Het cortex. Importantly, conditional Mef2c heterozygosity in forebrain excitatory neurons reproduced a subset of the Mef2c-Het phenotypes, while conditional Mef2c heterozygosity in microglia reproduced social deficits and repetitive behavior. CONCLUSIONS Taken together, our findings show that mutations found in individuals with MCHS disrupt the DNA-binding function of MEF2C, and DNA binding-deficient Mef2c global heterozygous mice display numerous MCHS-related phenotypes, including excitatory neuron and microglia gene expression changes. Our findings suggest that MEF2C regulates typical brain development and function through multiple cell types, including excitatory neuronal and neuroimmune populations.
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Affiliation(s)
- Adam J. Harrington
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Catherine M. Bridges
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC;,Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC
| | - Stefano Berto
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX
| | - Kayla Blankenship
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Jennifer Y. Cho
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC;,Medical Scientist Training Program, Medical University of South Carolina, Charleston, SC
| | - Ahlem Assali
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Benjamin M. Siemsen
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC;,Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston, SC
| | | | - Evgeny Tsvetkov
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Acadia Thielking
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Genevieve Konopka
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Michael D. Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC;,Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston, SC
| | | | - Christopher W. Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC;,Correspondence:
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8
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Sucharov J, Ray K, Brooks EP, Nichols JT. Selective breeding modifies mef2ca mutant incomplete penetrance by tuning the opposing Notch pathway. PLoS Genet 2019; 15:e1008507. [PMID: 31790396 PMCID: PMC6907857 DOI: 10.1371/journal.pgen.1008507] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 12/12/2019] [Accepted: 11/04/2019] [Indexed: 02/07/2023] Open
Abstract
Deleterious genetic mutations allow developmental biologists to understand how genes control development. However, not all loss of function genetic mutants develop phenotypic changes. Many deleterious mutations only produce a phenotype in a subset of mutant individuals, a phenomenon known as incomplete penetrance. Incomplete penetrance can confound analyses of gene function and our understanding of this widespread phenomenon remains inadequate. To better understand what controls penetrance, we capitalized on the zebrafish mef2ca mutant which produces craniofacial phenotypes with variable penetrance. Starting with a characterized mef2ca loss of function mutant allele, we used classical selective breeding methods to generate zebrafish strains in which mutant-associated phenotypes consistently appear with low or high penetrance. Strikingly, our selective breeding for low penetrance converted the mef2ca mutant allele behavior from homozygous lethal to homozygous viable. Meanwhile, selective breeding for high penetrance converted the mef2ca mutant allele from fully recessive to partially dominant. Comparing the selectively-bred low- and high-penetrance strains revealed that the strains initially respond similarly to the mutation, but then gene expression differences between strains emerge during development. Thus, altered temporal genetic circuitry can manifest through selective pressure to modify mutant penetrance. Specifically, we demonstrate differences in Notch signaling between strains, and further show that experimental manipulation of the Notch pathway phenocopies penetrance changes occurring through selective breeding. This study provides evidence that penetrance is inherited as a liability-threshold trait. Our finding that vertebrate animals can overcome a deleterious mutation by tuning genetic circuitry complements other reported mechanisms of overcoming deleterious mutations such as transcriptional adaptation of compensatory genes, alternative mRNA splicing, and maternal deposition of wild-type transcripts, which are not observed in our system. The selective breeding approach and the resultant genetic circuitry change we uncovered advances and expands our current understanding of genetic and developmental resilience. Some deleterious gene mutations only affect a subset of genetically mutant animals. This widespread phenomenon, known as mutant incomplete penetrance, complicates discovery of causative gene mutations in both model organisms and human disease. This study utilized the zebrafish mef2ca transcription factor mutant that produces craniofacial skeleton defects with incomplete penetrance. Selectively breeding zebrafish families for low- or high-penetrance mutants for many generations created different zebrafish strains with consistently low or high penetrance. Comparing these strains allowed us to gain insight into the mechanisms that control penetrance. Specifically, genes under the control of mef2ca are initially similarly expressed between the two strains, but differences between strains emerge during development. We found that genetic manipulation of these downstream genes mimics the effects of our selective breeding. Thus, selective breeding for penetrance can change the genetic circuitry downstream of the mutated gene. We propose that small differences in gene circuitry between individuals is one mechanism underlying susceptibility or resilience to genetic mutations.
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Affiliation(s)
- Juliana Sucharov
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Kuval Ray
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Elliott P. Brooks
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - James T. Nichols
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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9
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Tu S, Akhtar MW, Escorihuela RM, Amador-Arjona A, Swarup V, Parker J, Zaremba JD, Holland T, Bansal N, Holohan DR, Lopez K, Ryan SD, Chan SF, Yan L, Zhang X, Huang X, Sultan A, McKercher SR, Ambasudhan R, Xu H, Wang Y, Geschwind DH, Roberts AJ, Terskikh AV, Rissman RA, Masliah E, Lipton SA, Nakanishi N. NitroSynapsin therapy for a mouse MEF2C haploinsufficiency model of human autism. Nat Commun 2017; 8:1488. [PMID: 29133852 PMCID: PMC5684358 DOI: 10.1038/s41467-017-01563-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 09/27/2017] [Indexed: 01/07/2023] Open
Abstract
Transcription factor MEF2C regulates multiple genes linked to autism spectrum disorder (ASD), and human MEF2C haploinsufficiency results in ASD, intellectual disability, and epilepsy. However, molecular mechanisms underlying MEF2C haploinsufficiency syndrome remain poorly understood. Here we report that Mef2c +/-(Mef2c-het) mice exhibit behavioral deficits resembling those of human patients. Gene expression analyses on brains from these mice show changes in genes associated with neurogenesis, synapse formation, and neuronal cell death. Accordingly, Mef2c-het mice exhibit decreased neurogenesis, enhanced neuronal apoptosis, and an increased ratio of excitatory to inhibitory (E/I) neurotransmission. Importantly, neurobehavioral deficits, E/I imbalance, and histological damage are all ameliorated by treatment with NitroSynapsin, a new dual-action compound related to the FDA-approved drug memantine, representing an uncompetitive/fast off-rate antagonist of NMDA-type glutamate receptors. These results suggest that MEF2C haploinsufficiency leads to abnormal brain development, E/I imbalance, and neurobehavioral dysfunction, which may be mitigated by pharmacological intervention.
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Affiliation(s)
- Shichun Tu
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA.
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
| | - Mohd Waseem Akhtar
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Rosa Maria Escorihuela
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
- Departament de PsiquiatriaiMedicina Legal, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Alejandro Amador-Arjona
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Vivek Swarup
- Center for Autism Research and Treatment (CART), University of California, Los Angeles, CA, 90095, USA
| | - James Parker
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Jeffrey D Zaremba
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Timothy Holland
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Neha Bansal
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Daniel R Holohan
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Kevin Lopez
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Scott D Ryan
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Shing Fai Chan
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Li Yan
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Xiaofei Zhang
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Xiayu Huang
- Bioinformatics Core Facility, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Abdullah Sultan
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Scott R McKercher
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
- Department of Molecular Medicine and Neuroscience, Neuroscience Translational Center, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Rajesh Ambasudhan
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Huaxi Xu
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Yuqiang Wang
- Institute of New Drug Research, Jinan University College of Pharmacy, Guangzhou, 510632, China
| | - Daniel H Geschwind
- Center for Autism Research and Treatment (CART), University of California, Los Angeles, CA, 90095, USA
| | - Amanda J Roberts
- Department of Neuroscience and Mouse Behavioral Assessment Core, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Alexey V Terskikh
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
- Veterans Affairs San Diego Healthcare System, San Diego, CA, 92161, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
- National Institute on Aging, NIH, Bethesda, MD, 20892, USA
| | - Stuart A Lipton
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA.
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
- Department of Molecular Medicine and Neuroscience, Neuroscience Translational Center, The Scripps Research Institute, La Jolla, CA, 92037, USA.
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA.
| | - Nobuki Nakanishi
- Neurodegenerative Disease Center, Scintillon Institute, San Diego, CA, 92121, USA.
- Neuroscience and Aging Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
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10
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Yang YJ, Yao X, Guo J, Zhao R, He XY, Zhao L, Tu M, Zhu YM. Interstitial deletion 5q14.3q21.3 associated with lethal epilepsy. Am J Med Genet A 2015; 167A:866-71. [PMID: 25706510 DOI: 10.1002/ajmg.a.36991] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 12/05/2014] [Indexed: 12/29/2022]
Affiliation(s)
- Yong-jia Yang
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Xu Yao
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Jihong Guo
- State Key Laboratory of Medical Genetics; Central South University; Changsha China
| | - Rui Zhao
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Xin-yu He
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Liu Zhao
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Ming Tu
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
| | - Yi-min Zhu
- The Laboratory of Genetics and Metabolism; Hunan Children's Research Institute (HCRI), Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
- Department of Emergency, Hunan Children's Hospital; The Paediatric Academy of University of South China; Changsha China
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11
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Tanteles GA, Alexandrou A, Evangelidou P, Gavatha M, Anastasiadou V, Sismani C. PartialMEF2Cdeletion in a Cypriot patient with severe intellectual disability and a jugular fossa malformation: Review of the literature. Am J Med Genet A 2015; 167A:664-9. [DOI: 10.1002/ajmg.a.36945] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/07/2014] [Indexed: 02/06/2023]
Affiliation(s)
- George A. Tanteles
- Clinical Genetics Department; The Cyprus Institute of Neurology and Genetics & Archbishop Makarios III Medical Centre; Nicosia Cyprus
| | - Angelos Alexandrou
- Cytogenetics and Genomics Department; The Cyprus Institute of Neurology and Genetics; Nicosia Cyprus
| | - Paola Evangelidou
- Cytogenetics and Genomics Department; The Cyprus Institute of Neurology and Genetics; Nicosia Cyprus
| | - Marina Gavatha
- Pediatric Neurology Department; Archbishop Makarios III Medical Centre; Nicosia Cyprus
| | - Violetta Anastasiadou
- Clinical Genetics Department; The Cyprus Institute of Neurology and Genetics & Archbishop Makarios III Medical Centre; Nicosia Cyprus
| | - Carolina Sismani
- Cytogenetics and Genomics Department; The Cyprus Institute of Neurology and Genetics; Nicosia Cyprus
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12
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Sakai Y, Ohkubo K, Matsushita Y, Akamine S, Ishizaki Y, Torisu H, Ihara K, Sanefuji M, Kim MS, Lee KU, Shaw CA, Lim J, Nakabeppu Y, Hara T. Neuroendocrine phenotypes in a boy with 5q14 deletion syndrome implicate the regulatory roles of myocyte-specific enhancer factor 2C in the postnatal hypothalamus. Eur J Med Genet 2013; 56:475-83. [DOI: 10.1016/j.ejmg.2013.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 06/19/2013] [Indexed: 02/07/2023]
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13
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Hotz A, Hellenbroich Y, Sperner J, Linder-Lucht M, Tacke U, Walter C, Caliebe A, Nagel I, Saunders DE, Wolff G, Martin P, Morris-Rosendahl DJ. Microdeletion 5q14.3 and anomalies of brain development. Am J Med Genet A 2013; 161A:2124-33. [DOI: 10.1002/ajmg.a.36020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 03/31/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Alrun Hotz
- Institute of Human Genetics; Albert-Ludwigs University Medical Centre Freiburg; Freiburg Germany
| | | | | | - Michaela Linder-Lucht
- Zentrum für Kinder- und Jugendmedizin; Albert-Ludwigs-Universitätsklinikum Freiburg; Freiburg Germany
| | - Uta Tacke
- Zentrum für Kinder- und Jugendmedizin; Albert-Ludwigs-Universitätsklinikum Freiburg; Freiburg Germany
| | - Caren Walter
- Institute of Human Genetics; Albert-Ludwigs University Medical Centre Freiburg; Freiburg Germany
| | - Almuth Caliebe
- Institut für Humangenetik; Christian-Albrechts-Universität Kiel; Kiel Germany
| | - Inga Nagel
- Institut für Humangenetik; Christian-Albrechts-Universität Kiel; Kiel Germany
| | - Dawn E. Saunders
- Department of Radiology; Great Ormond Street Hospital; London United Kingdom
| | - Gerhard Wolff
- Institute of Human Genetics; Albert-Ludwigs University Medical Centre Freiburg; Freiburg Germany
| | - Peter Martin
- Séguin Klinik; Epilepsiezentrum Kehl-Kork; Kork Germany
| | - Deborah J. Morris-Rosendahl
- Institute of Human Genetics; Albert-Ludwigs University Medical Centre Freiburg; Freiburg Germany
- National Heart and Lung Institute; Imperial College, London; London United Kingdom
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14
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Wilson GN. TheMEF2Cgene-microdeletion 5q14.3 dilemma and three axioms for molecular syndromology. Am J Med Genet A 2013; 161A:916-7. [DOI: 10.1002/ajmg.a.35785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 10/28/2012] [Indexed: 11/12/2022]
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15
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Novara F, Rizzo A, Bedini G, Girgenti V, Esposito S, Pantaleoni C, Ciccone R, Sciacca FL, Achille V, Della Mina E, Gana S, Zuffardi O, Estienne M. MEF2C deletions and mutations versus duplications: a clinical comparison. Eur J Med Genet 2013; 56:260-5. [PMID: 23402836 DOI: 10.1016/j.ejmg.2013.01.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 01/23/2013] [Indexed: 11/29/2022]
Abstract
5q14.3 deletions including the MEF2C gene have been identified to date using genomic arrays in patients with severe developmental delay or intellectual disability, stereotypic behavior, epilepsy, cerebral malformations and a facial gestalt not really distinctive though characterized by broad and/or high, bulging forehead, upslanting palpebral fissures, flat nasal root and bridge, small, upturned nose, hypotonic small mouth resulting in cupid bow/tented upper lip. MEF2C mutations have been also identified in patients with overlapping phenotype so that it is considered the gene responsible for the 5q14.3 deletion syndrome. To date, one single duplication including MEF2C has been reported in a patient with intellectual disability but its clinical significance remains uncertain also because of the large size of the imbalance. Here we present two further patients with 5q14.3 duplications including MEF2C. Their phenotype indeed suggest the pathogenic effect of the MEF2C duplication although other duplicated genes also brain expressed might contribute to the clinical features. In none of them a clear-cut syndrome can be identified. A comparison between MEF2C deleted/mutated and duplicated patients is also presented.
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Affiliation(s)
- Francesca Novara
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
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16
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MEF2C Haploinsufficiency features consistent hyperkinesis, variable epilepsy, and has a role in dorsal and ventral neuronal developmental pathways. Neurogenetics 2013; 14:99-111. [PMID: 23389741 DOI: 10.1007/s10048-013-0356-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/23/2013] [Indexed: 12/11/2022]
Abstract
MEF2C haploinsufficiency syndrome is an emerging neurodevelopmental disorder associated with intellectual disability, autistic features, epilepsy, and abnormal movements. We report 16 new patients with MEF2C haploinsufficiency, including the oldest reported patient with MEF2C deletion at 5q14.3. We detail the neurobehavioral phenotype, epilepsy, and abnormal movements, and compare our subjects with those previously reported in the literature. We also investigate Mef2c expression in the developing mouse forebrain. A spectrum of neurofunctional deficits emerges, with hyperkinesis a consistent finding. Epilepsy varied from absent to severe, and included intractable myoclonic seizures and infantile spasms. Subjects with partial MEF2C deletion were statistically less likely to have epilepsy. Finally, we confirm that Mef2c is present both in dorsal primary neuroblasts and ventral gamma-aminobutyric acid(GABA)ergic interneurons in the forebrain of the developing mouse. Given interactions with several key neurodevelopmental genes such as ARX, FMR1, MECP2, and TBR1, it appears that MEF2C plays a role in several developmental stages of both dorsal and ventral neuronal cell types.
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Zweier M, Rauch A. The MEF2C-Related and 5q14.3q15 Microdeletion Syndrome. Mol Syndromol 2012; 2:164-170. [PMID: 22670137 DOI: 10.1159/000337496] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Disorders related to the autosomal transcription factor MEF2C located in 5q14.3 were first described in 2009 and have since evolved to one of the more common microdeletion syndromes. Mutational screening in a larger cohort revealed heterozygous de novo mutations of MEF2C in about 1% of patients with moderate to severe intellectual disability, and the phenotype is similar in patients with intragenic deletions and multigenic microdeletions. Clinically, MEF2C-related disorders are characterized by severe intellectual disability with absent speech and limited walking abilities, hypotonia, seizures, and a variety of minor brain anomalies. The majority of patients show a similar facial gestalt with broad forehead, flat nasal bridge, hypotonic mouth, and small chin, as well as strabismus, but this phenotype is clinically not well recognized. The course of the disease is generally quite uniform, but patients with point mutations and smaller deletions seem to have a higher chance of walking skills and a lower risk of refractory seizures. Patients in whom the microdeletion also includes the RASA1 gene show features of the respective capillary and arterio-venous malformations and fistula syndrome. The phenotypic overlap with Rett syndrome is explained by a shared pathway and, accordingly, diminished MECP2 and CDKL5 expression is measureable in patients with MEF2C defects. Further research of this pathway may therefore eventually lead to a common therapeutic target.
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Affiliation(s)
- M Zweier
- Institute of Human Genetics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
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